This invention relates to a filtration system and particularly to a filter assembly for removing particulate matter from coolant employed in optical corrective lens grinding operations.
Grinding and edging machines are used during the production of glass and plastic optical corrective lenses. These machines typically use rotating abrasive grinding wheels which remove material from a lens blank to produce a finished lens. This operation is typically carried out with the use of a liquid coolant fluid which lubricates the grinding wheel and blank, cools the workpiece and tool, and carries away particulates generated by the grinding operation. Since the coolant fluid is ordinarily recycled, it is desirable to provide a filter device which removes most of the particulates from the coolant fluid before it is recycled and again used in the grinding or edging machine. Absent a filtration system, the presence of particulate matter in the recycled coolant can lead to grinding inaccuracies and surface imperfections in the finished lens. Additionally, filtering the coolant fluid promotes the life of grinding wheels used in lens finishing machines. In addition to the desirability of providing a filtration system for the coolant fluid, it is further desirable to provide a filter assembly which will operate for an extended period of time without cleaning or replacement. It is further desirable to provide a filter assembly adapted to be used in connection with existing lens grinding and edging machinery without significant modification. In accordance with this invention, a coolant filtering system is provided having the above-mentioned desirable features.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.